<!doctype html>
<html>

<head>
	<title>Doughnut Chart</title>
	<script src="../../Chart.bundle.js"></script>
	<script src="../utils.js"></script>
	<style>
	canvas {
		-moz-user-select: none;
		-webkit-user-select: none;
		-ms-user-select: none;
	}
	</style>
</head>

<body>
	<div id="canvas-holder" style="width:40%">
		<canvas id="chart-area"></canvas>
	</div>
	<button id="randomizeData">Randomize Data</button>
	<button id="addDataset">Add Dataset</button>
	<button id="removeDataset">Remove Dataset</button>
	<button id="addData">Add Data</button>
	<button id="removeData">Remove Data</button>
	<script>
		var randomScalingFactor = function() {
			return Math.round(Math.random() * 100);
		};

		var config = {
			type: 'doughnut',
			data: {
				datasets: [{
					data: [
						randomScalingFactor(),
						randomScalingFactor(),
						randomScalingFactor(),
						randomScalingFactor(),
						randomScalingFactor(),
					],
					backgroundColor: [
						window.chartColors.red,
						window.chartColors.orange,
						window.chartColors.yellow,
						window.chartColors.green,
						window.chartColors.blue,
					],
					label: 'Dataset 1'
				}],
				labels: [
					'Red',
					'Orange',
					'Yellow',
					'Green',
					'Blue'
				]
			},
			options: {
				responsive: true,
				legend: {
					position: 'top',
				},
				title: {
					display: true,
					text: 'Chart.js Doughnut Chart'
				},
				animation: {
					animateScale: true,
					animateRotate: true
				}
			}
		};

		window.onload = function() {
			var ctx = document.getElementById('chart-area').getContext('2d');
			window.myDoughnut = new Chart(ctx, config);
		};

		document.getElementById('randomizeData').addEventListener('click', function() {
			config.data.datasets.forEach(function(dataset) {
				dataset.data = dataset.data.map(function() {
					return randomScalingFactor();
				});
			});

			window.myDoughnut.update();
		});

		var colorNames = Object.keys(window.chartColors);
		document.getElementById('addDataset').addEventListener('click', function() {
			var newDataset = {
				backgroundColor: [],
				data: [],
				label: 'New dataset ' + config.data.datasets.length,
			};

			for (var index = 0; index < config.data.labels.length; ++index) {
				newDataset.data.push(randomScalingFactor());

				var colorName = colorNames[index % colorNames.length];
				var newColor = window.chartColors[colorName];
				newDataset.backgroundColor.push(newColor);
			}

			config.data.datasets.push(newDataset);
			window.myDoughnut.update();
		});

		document.getElementById('addData').addEventListener('click', function() {
			if (config.data.datasets.length > 0) {
				config.data.labels.push('data #' + config.data.labels.length);

				var colorName = colorNames[config.data.datasets[0].data.length % colorNames.length];
				var newColor = window.chartColors[colorName];

				config.data.datasets.forEach(function(dataset) {
					dataset.data.push(randomScalingFactor());
					dataset.backgroundColor.push(newColor);
				});

				window.myDoughnut.update();
			}
		});

		document.getElementById('removeDataset').addEventListener('click', function() {
			config.data.datasets.splice(0, 1);
			window.myDoughnut.update();
		});

		document.getElementById('removeData').addEventListener('click', function() {
			config.data.labels.splice(-1, 1); // remove the label first

			config.data.datasets.forEach(function(dataset) {
				dataset.data.pop();
				dataset.backgroundColor.pop();
			});

			window.myDoughnut.update();
		});
	</script>
</body>

</html>
